Underreamer



Oct. 15, 1929, C5., H, TERRELL i 11,731,732

UNDERREAMER Filed Deo. l0. 1928 2 Sheets-,Sheet 1 26 i :FI E- l \F Q25 @wwe/who@ With the foregoi `Patented Oct. l5, 1929 GEORGE E. TEBBELI'., or

SAN ANTONIO, TEXAS UNDEBREAIEB.

Animation med' December 1o, 192s. serial No. 324,92

The invention relates to improvements in underreamers for enlarging the lowerends of holds formed with post-hole augers or the like, permitting cement when'poured into the 5 holes to have an enlarged footlng.

The device isof the general type embodying a rotatable .earth-receiving pan and an outwardly and downwardly swingable cutter for enlarging the lower end of the hole ande 1e directing the loosened dirt into the pan to be removed by the latter upon removal of the tool, and it is theprincipal object of the invention to provide a new and improved construction which is exceptionally simple and 15 inexpensive, yet is eiicient, reliable, longlived and generally desirable.

To upwardly and downwardly 'swing the cutter, means are provided embodying a link pivoted to the outer endof the cutter, and it. is another object of the invention to so relatel this link with other parts as` to cause it to effectively brace the cutter, holding the latter against any tendency to lag-I and unduly strain its pivot.

'ng in view, the invention resides in the novel subject matter hereinafter described and claimed, description being aecomplished by reference tothe accompanying drawings. 1

Fig. 1 is a si in use.

Fig. 2 is an broken away and vin section, the parts b the same positions as in Fig. 1.

Fig. 3 is a fragmentary side elevation showing the tool in condition for insertion into or withdrawal from the hole.

Fig. 4 is a horizontal sectional 4--4 of Fig. '2. MF Fig. 5 is a similar view on line 5-5 of i 3. Fig. 6 is a detail transverse sectional .view online(- 6ofFigs.2and4c.V W f The form of construction herein illustrated has proven to meet all requirements in an effectlve mannerA and this construction will be specifically explained, with the understanding that withinthe scope of the invention as claimed, variations may be made.

6o The numeral 8 denotes an earth-receiving de elevation showing thedevicev enlarged side elevation partly eing in viewon line` The wall portions'll are pivoted at 14 to the '.wall portions 9 of the pan 8, so that the two cutters vmay swing to and from vertical and therethrou h.-

pan of substantially circular outline although its side wall is preferably provided with two parallel flattened portions 9, said wall being formed with notches 10, one of which is adjacent one ofthe flat portions 9 whilethe other is adjacent theother of these ortions. Two cutters 1 1 extend through tlie notches 10 res tively when in operative position and eac cutter embodies a substantially horizontal bottom portion 12 and a vertical wall 13 rising therefrom, the cutters being transversely curved so that the two portions 12-13 merge gradually into /each other as shown.

horizontal positions'. The bottom portion 12 of each cutter has its inner 12 disposed at an acute angle to the wall portion 13 so that the free longitudinal edge 'of said bottom portion 12 ,is relatively short and does not lie upon the bottom of the panv 8`when the cutters are eX- tended. Thus, there `is no danger of earth bemg jammed betweenthecutter .bottoms 12 and the pan bottom and -interfering with 76 -maximum downward swinging of the cutters. The walls 13 are longitudinally curved as shown most clearly in Fig. 4, their free ends are provided with inwardly, projectinglugsb" 15 spacedabove' the bottom portions 12, and S0 said walls decrease in height toward said lugs.

The free edges of the bottom portions 12 are 4 provided with cutting blades 16 detachably vsecured thereto by any desired means 17 so that a type of blade suitable to the earth in e5 v'vhich the tool must ue operated, may bevapplied. As the tool vis: rotated, the cutters 11 cut the earth vand direct it into the pan 8 and when this pan is about full andthe tool must be removed to dump its contents, the cutters A 11 are swung upwardly as shown in Fig 3, at which timesaid cutters substantially close the notches 10 to prevent discharge of earth A rigid' ame structure issecured to and 95 r'ises fromthe pan 8. In the present showing, the lower ends of two vertical bars 18 are welded or otherwise secured tothe side walls of the pan 8 at the Aedges of the notches 10. remote from the pivots 14.l Near their lower A100 ends, these bars 18 are provided with inwardly olfset portions 19 which receive the outer ends of the cutter walls 13 when t-he cutters 11 are upwardly swung as in Fig. 3, said portions 19 being rigidly connected with each other by a lug o r block 20 to which they are preferably welded. Above the portions 19, the bars 18 are parallel and their upper ends are welded or otherwise secured to a head 21 of circular form. This head preferably comprise; a metal ring 22 welded to the upper ends of the bars 18, and a metal plate 23 spanning said ring and welded both to the latter and to the upper lextremities of said bars. This plate 23 is formed with a central opening 24 through which a vertical drive rod 25 passes slidably, the upper end of said drive rod having an appropriate handle 26 while its lower end is rigidly secured in any desired manner to a cross-head 27. This cross-head is 'provided with guide sleeves 28 which are l slidable upon the parallel upper portions of the bars 18, and inthe present showing, said cross head is equipped with a downwardly projecting, flat-sided `lug 29. Two links 30 preferably of angle metal, have their upper ends pivoted at 31 tothe lug 29 while their lower endsare pivoted at 32 yto the lugs 15 of the cutters 11.l These links co-operate with the cross-head 2'( and thedrive rod 25 in upwardly swinging the cutters 11 when the handle 2,6r is raised, and in projecting said cutters when said handle is forced downwardly, and when the cutters are in operative position as seen in Figs. 1, 2 and 4, the links 30 `bear solidly lagainst the portions 19 of the bars 18. By so doing, they effectively brace the cutters .11 so that the outer ends of the lattercan have no tendency to lag and pry rearwardly, with danger of loosening the pivots 14 or otherwise injuring the cutters o r the pan 8.

The bottom of the pan 8 is provided with a spike 33 to enter the earth at the bottom of the hole being underreamed, thereby c entering the ,lower portion of the reamer while the circular head 21 centers itsgupper end. By preference, the aforesaid pan bottom is formed with two lslots 34 extending from its center to its periphery and is provided alongr p the rearedges of these slots with cutters 35. These cutters serve to elevate loose dirt from the bottom of the hole and direct it into the an 8. i i u p In operating the invention, it .is positioned as seen lin Fig. 3 and is then lowered into thejhole whose lower` end is to be underreamed. Then, by forcing downwardly upon the handle 26 .and rotating the entire tool by meansof this handle, the cutters 11 operate upon the earth and direct the dirt which they cut into the pan 8. When this pan is about full, the handle 26 is pulled upwardly, thereby upwardly swinging the cutters 11 vand causing them to substantially close the notches 10 so that the earth in the pan is confined and is readily removed by withdrawing the entire tool from the hole. After dumping of this earth, the tool is again inserted and the operation above described is repeated. "When the pan is again substantially full, the cutters are again swung upwardly and the tool withdrawn from the hole to discharge the dirt, and these operations are repeated as many times as may be neces. sary until the lower portion of the hole is enlarged the required extent as seen in Fig. 1.

Not only is the construction of the device comparatively simple and inexpensive, but

lsaid construction is of such nature that the .applied to the tool according to the character of the soil i-n which it must operate.

Attention is again invited to the fact that while the preferred construction has been shown and described, variations may be made within the scope of the invention-as claimed.

I claim 1. An underreamer comprising a vertically elongated rigid frame vhaving a rod guide at its upper end, an earth-receiving pan secured tothe lower c nd of said frame, the side wall of said pan being formed with a notch, a cutter pivoted to said pan and extending through said notch, said cutter being shaped to-direct the earth cut thereby into the pan, a crosshead slidably mounted on the frame for vertical movement, a driving rod passingslidablyVv through the aforesaid rod guide and secured to saidI cross-head for rotating the entire tool and for raising and lowering said cross-head, and a link pivoted to said cross-head and said cutter for projecting the latter upon lowering of said cross-head and for upwardly swinging said cutter upon lifting of said cross-head.

2. An underreamer comprising an earthreceiving pan whose side wall is formed with a notch, a cutter pivoted to the pan and extending shaped to direct the earth cut thereby into the pan, two vertical bars secured to and rising from said pan, said bars having parallel portions, a circular head secured to the upper ends of said bars and having a rod guide disposed centrally between them,y a cross-head having guide sleeves on its ends slidably surrounding said parallel portions of said bars, through the aforesaid guide and secured at its lower end to said cross-head, and a link pivoted to said cross-head and said cutter for projecting said cutter when the cross-head through said notch, said cutter being` a drive rod passing slidably' is lowered and for u wardly swinging said cutter upon raising o said cross-head. Y 3'. A structure as specified in claim 2; said link extending across and contactin with one 5 of said sidebars'when the cutter -1s in pro. jeoted position, thereby preventing said cutter from having a tendency to lag and pry upon its-pivot.

4. A structure as specified in claim 1; said i cutter being so shaped and pivoted as to substantially close said notch when raised.

5. A structure as specified in claim 1; saidcutter being pivoted to said pan at'one side of said frame, said link being disposed at the other side of said frame, the cutter being provided with a side wall curved to the link, said frame havin an inward oiset which'receives said curve cutter wall when the cut.-

ter is upwardly swung. In testimony whereof I have hereunto affixed my signature.

GEORGE H. TERRELL. 

